The present invention is directed to a transmission and reception module for a bidirectional communication network, particularly a broadband ISDN, wherein the module includes a housing which contains an optical transmitter for transmitting a first light wavelength along a first beam path, has a first lens and a second lens arranged in succession on the first beam path with the first lens focussing a divergent light from the transmitter towards a beam of parallel waves and the second lens further focussing the beam to a focal point at which an end of an optical fiber is held by a portion of the housing. A light beam separating device is arranged in the first beam path between the first and second lenses and is at least partially transmissive to the light of the first wavelength while being partially reflective of light of the second wavelength to branch off or divide off a portion of the second wavelength along a second optical path, a detector which is sensitive to the second wavelength is positioned on the second path for converting electrical signals contained in the beam of the second wavelength.
In transmission and reception modules of the above-mentioned type, problems occur with the maladjustment of the various parts.